No to Stephen King, the adult Roald Dahls etc. Inappropriate for age 10, content wise.
And no to the vast majority of "classics" for a reluctant reader. You'll put him off for life.
If he likes humorous books above all, then try some of the slightly more challenging series as indicated above. David Baddiel books are great and there are lots of great standalone novels appropriate for his age like The Life of Riley by Simon James Green, The Worst Holiday Ever by Charlie Higson.
If he might like fantasy, then Cressida Cowell, Rick Riordan (not just Percy Jackson, the Egyptian series The Kane Chronicles is ace) the younger Pratchetts would all be good.
Don't forget non-fiction. Boys, and particularly boys on the spectrum, can go through a phase of preferring non-fiction. Just seize on any interests. If he likes nature, Dara MacAnulty's nature book might inspire (he's a young teen with autism himself, already published!)
And don't write off graphic novels and comics. They count as reading. Expensive, as so quick to read, but might get him into the library if you find one to buy thar he loves first.
No Dickens or Austen, please. You'll stop him reading for good